The present invention is directed to a heat-shrinkable sleeve or envelope consisting of at least one heat-shrinkable component and a mechanically reinforcing component.
British Patent No. 1,497,051, which was the basis of German Gebrauchsmuster 75 01 913, discloses a heat-shrinkable sleeve which includes reinforcing elements in order to reinforce the mechanical properties. However, these elements only extend in a longitudinal direction and are used so that the direction of shrinkage of the sleeve is not influenced by the elements. The result of this structure is that damage to the sleeve, such as, for example, tears in a longitudinal direction, can continue unobstructed. This is particularly dangerous when such damage occurs during assembly of the sleeve, because then during shrinkage of the sleeve further tearing in the longitudinal direction of the sleeve as a result of the shrinkage forces cannot be stopped.
To overcome this problem, for example, cloth or fabrics are used in the European Patent No. 0,117,026, which discloses utilizing a shrinkable fabric which is embedded in a non-shrinkable material. In order to achieve a corresponding high mechanical stability, these fabrics, in addition to the shrinkable fibers which extend in the first shrinking direction, also include non-shrinkable heat-resistant fibers which extend in a second direction of the fabric. Thus, also in the case of these inclusions, fundamentally, only one direction is protected from damage. On the other hand, the production of sleeves consisting of fabrics of this type require a considerable higher outlay than the conventional type and which, by a laminar or tubular extrusion, the required surface structure is already obtained in its unprocessed form.